Intercooled cooling air with improved air flow

Abstract

A gas turbine engine comprises a main compressor section having a high pressure compressor with a downstream discharge, and more upstream locations. A turbine section has a high pressure turbine. A tap taps air from at least one of the more upstream locations in the compressor section, passes the tapped air through a heat exchanger and then to a cooling compressor. The cooling compressor compresses air downstream of the heat exchanger, and delivers air into the high pressure turbine. The cooling compressor includes a downstream connection that delivers discharge pressure air to an upstream location in the high pressure turbine and a second tap from an intermediate pressure location within the cooling compressor. The second tap is connected to a downstream location within the high pressure turbine. An intercooling system for a gas turbine engine is also disclosed.

What is claimed is: 
     
       1. A gas turbine engine comprising;
 a main compressor section having a high pressure compressor with a downstream discharge, and more upstream locations; 
 a turbine section having a high pressure turbine; 
 a tap tapping air from at least one of said more upstream locations in said compressor section, passing said tapped air through a heat exchanger and then to a cooling compressor, said cooling compressor compressing air downstream of said heat exchanger, and delivering air into said high pressure turbine; and 
 said cooling compressor including a downstream connection for delivering discharge pressure air to an upstream location in said high pressure turbine and a second tap from an intermediate pressure location within said cooling compressor, and said second tap being connected to a downstream location within said high pressure turbine without further compression. 
 
     
     
       2. The gas turbine engine as set forth in  claim 1 , wherein air is also tapped from said downstream discharge of said high pressure compressor and mixed with air in said downstream connection before the mixed air is delivered to said upstream location in said high pressure turbine. 
     
     
       3. The gas turbine engine as set forth in  claim 2 , wherein said upstream location in said high pressure turbine is a first stage of said high pressure turbine. 
     
     
       4. The gas turbine engine as set forth in  claim 2 , wherein a main fan delivers bypass air into a bypass duct and into said heat exchanger positioned within said bypass duct to be cooled by bypass air. 
     
     
       5. The gas turbine engine as set forth in  claim 2 , wherein said cooling compressor includes a centrifugal compressor impeller. 
     
     
       6. The gas turbine engine as set forth in  claim 2 , wherein air temperatures at said downstream most location of said high pressure compressor are greater than or equal to 1350° F. 
     
     
       7. The gas turbine engine as set forth in  claim 2 , wherein said turbine section driving a bull gear, said bull gear further driving an impeller of said cooling compressor. 
     
     
       8. The gas turbine engine as set forth in  claim 7 , wherein said bull gear also driving an accessory gearbox. 
     
     
       9. The gas turbine engine as set forth in  claim 8 , wherein a gear ratio multiplier is included such that said impeller rotates at a faster speed than said tower shaft. 
     
     
       10. The gas turbine engine as set forth in  claim 7 , wherein said impeller is a centrifugal compressor impeller. 
     
     
       11. The gas turbine engine as set forth in  claim 10 , wherein an auxiliary fan is positioned upstream of the heat exchanger. 
     
     
       12. The gas turbine engine as set forth in  claim 1 , wherein an auxiliary fan is positioned upstream of the heat exchanger. 
     
     
       13. The gas turbine engine as set forth in  claim 12 , wherein said auxiliary fan operates at a variable speed. 
     
     
       14. The gas turbine engine as set forth in  claim 1 , wherein air temperatures at said downstream most location of said high pressure compressor are greater than or equal to 1350° F. 
     
     
       15. An intercooling system for a gas turbine engine comprising:
 a heat exchanger for cooling air drawn from a portion of a main compressor section at a first temperature and pressure for cooling the air to a second temperature cooler than the first temperature; 
 a cooling compressor compressing air communicated from the heat exchanger to a second pressure greater than the first pressure and for communicating the compressed air to a portion of a turbine section; and 
 said cooling compressor including a downstream connection for delivering discharge pressure air to an upstream location in the high pressure turbine and a second tap tapped from an intermediate pressure location within said cooling compressor, and said second tap for being connected to a downstream location within the high pressure turbine without further compression. 
 
     
     
       16. The intercooling system as set forth in  claim 15 , wherein air is also tapped from said downstream discharge of said high pressure compressor and mixed with air in said downstream connection before the mixed air is delivered to said upstream location in said high pressure turbine. 
     
     
       17. The intercooling system as set forth in  claim 15 , wherein an auxiliary fan is positioned upstream of the heat exchanger. 
     
     
       18. The intercooling system as set forth in  claim 15 , wherein a bull gear drives an impeller of said cooling compressor. 
     
     
       19. The intercooling system as set forth in  claim 18 , wherein said bull gear also driving an accessory gearbox.